Defect-mediated ferroelectric domain depinning of polycrystalline BiFeO3 multiferroic thin films

• Published in: Applied physics letters Vol. 104; no. 9
• Main Authors: Bretos, I., Jiménez, R., Gutiérrez-Lázaro, C., Montero, I., Calzada, M. L.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 03-03-2014
• Subjects: Annealing; Applied physics; Bismuth ferrite; Current voltage characteristics; Defects; Ferroelectric domains; Ferroelectric materials; Ferroelectricity; Oxidation; Polycrystals; Thin films; Vacancies
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4867703

The ferroelectric domain depinning in a polycrystalline BiFeO3 film is studied by a defect-mediated diffusion mechanism driven by a secondary re-oxidation anneal. The presence of defect complexes (oxygen-vacancy-associated dipoles) responsible for pinning is discussed from the current-voltage (I-V) characteristics of the film. Dissociation of these complexes by re-oxidation anneal produces the effective depinning of domains in the material. The released oxygen vacancies would be compensated at the re-oxidized state due to the valence change of Fe2+ to Fe3+. Improvement on domain mobility results in a larger contribution to ferroelectric switching, showing a room-temperature remanent polarization of 67 μC cm−2.